White field chromaticity coordinates displayed by current display devices such as a liquid crystal display device, a plasma display device, a rear projection display device, and the like, are different from each other, more or less, due to the discrepancies among the displaying principles or hardware designs thereof. If a corresponding white balance adjustment is not executed to the white field chromaticity coordinate discrepancies of the display devices, there will be significant differences in the color display effect among different display devices. Accordingly, white balance tracing and corrections are usually executed during the manufacturing process of the display devices so that a color displayed by the respective display devices tends to be consistent.
Because spectral tristimulus values in a white field are mainly affected by spectral tristimulus values of a green color, therefore, when proceeding a white balance adjustment, the spectral tristimulus values of respective gray levels of the green color in the white field will be firstly obtained since the spectral tristimulus values of the respective gray levels of the green color in the whit field vary exponentially with the gray levels (this means the brightness of the green color exponentially varies with the gray level). Then, spectral tristimulus values of respective gray levels of a red color in the white field and spectral tristimulus values of respective gray levels of a blue color in the white field are adjusted to meet the requirements of the spectral tristimulus values of a white color in the whit field. The spectral tristimulus values of the respective gray levels of the red color in the whit field and the spectral tristimulus values of the respective gray levels of the blue color in the whit field will be obtained. The requirements of setting the chromaticity of all gray levels in the white field may not be satisfied when the spectral tristimulus values of the respective gray levels of the red color in the whit field and the spectral tristimulus values of the respective gray levels of the blue color in the whit field are adjusted in process, so there will be disparities between an adjusted white field and an expected white field.
Therefore, there is a need for a white balance adjusting method to solve the problems existing in the prior art.